Reacting to a report that President Barack Obama is mulling unilateral action that could impact almost half the nation's estimated 12 million illegal immigrants, Rep. Luis V. Gutiérrez said Monday, "It's music to my ears."

The Illinois Democrat, one of Congress' most vocal supporters of a comprehensive overhaul of the nation's immigration system, said in an appearance on MSNBC that Obama has been forced to take action because of gridlock in the House.

"We want to get as many as we can out of the vicious cycle of deportation," Gutiérrez said. "But I think if the president takes such a move ... I think it would be a huge move."

His comments came after reporter Chris Jansing told MSNBC's Jose Diaz-Balart that administration sources have said the White House is weighing executive action that would impact up to 5 million illegal immigrants. "If it is 5 million," Gutiérrez said, "That would be five times as many as when the president freed the 'Dreamers' from deportation — when he instituted [Deferred Action for Childhood Arrivals] in June of 2012, when he said we're not going to deport anymore immigrants that arrived here as children."

The Illinois Democrat told Diaz-Balart that he's talked with leaders in his hometown about gearing up to welcome thousands of newly legal residents into the city's systems.

"We have to get prepared as a city and prepare a model for the nation," he said. "Because when 5 million people are allowed the opportunity to come out from under the shadows and into the light of day and get legalized, it's going to take a lot of work and a lot of capacity of our community."

Diaz-Balart's brother, Florida Republican Rep. Mario Diaz-Balart, has worked with Gutiérrez to craft a bipartisan immigration overhaul in the House, but the effort collapsed this summer over GOP conservatives' concerns about security on the southern border.

Obama administration officials have told Hispanic groups that if Congress failed to act this summer, the president would take action on his own.